OHS Code Explanation Guide

Published Date: July 01, 2009
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Part 36 Mining

Section 747 Pillars

Subsection 747(1)

Underground mining activity in one property can inadvertently affect the safety of workers on an adjoining property. Consequently, both property owners are required to communicate for purposes of maintaining a safety pillar between the two adjoining properties, commonly known as a barrier pillar. The required pillar separation must be sufficient to separate activities and prevent mine ventilation air, gas and water from one mine entering the other. The required pillar separation must maintained on all working levels for all coal seams that are to be mined. To be equitable to both property owners, an appropriate portion of the required pillar must be left on each side of the common boundary.

Subsection 747(2)

Since portions of the remaining pillars will consist of material on each property, the respective owners are held responsible for ensuring that the composite pillar size is sufficient to ensure the safety of workers in each mine.

Subsection 747(3)

The technical factors that can contribute to pillar capability and stability are such that a professional engineer must determine the safe width of the pillar.

Subsection 747(4)

To avoid the potential for inadvertent over-excavation into the intended pillar, both property owners are held responsible for ensuring that no mining activities are conducted within 100 metres (330 feet) of the property boundary line between the two properties unless a professional engineer has authorized a smaller distance under subsection (3).

Subsection 747(5)

After the pillar design has been determined by a professional engineer and the physical barrier pillar limits have been reached, the employer is responsible for ensuring that no mining is performed within the barrier pillar itself. Again, for worker safety reasons the barrier pillar must remain intact.

Subsection 747(6)

Since minor surveying differences can negatively impact the intended width of the barrier pillar, this subsection allows the designated surveyor from one property to enter the mine on the adjoining property for purposes of confirming the final pillar width. Ideally both surveyors will conduct these survey checks and subsequently cross-check results to minimize the potential for error.

Subsection 747(7)

The location of all final workings immediately adjacent to the defined barrier pillar must be surveyed within 60 days of completion. The resultant plans for each property must be immediately filed with the Director.